1. Field of the Invention
The present invention relates to an image forming apparatus in which emissions from a fusing unit are trapped.
2. Description of Related Art
A conventional image forming apparatus as mentioned above is described in, for example, Japanese Patent Laid-Open Publication No. 2008-251514. This image forming apparatus has a duct provided above a fusing unit inside a frame. The duct includes a main section, which is a bottom-less cover disposed directly above the fusing unit, and a hollow cylindrical section extending from the main section. The cylindrical section is connected to an exhaust vent provided in the frame, and has an air duct portion inside of it.
The cylindrical section has an exhaust fan provided inside at the exhaust vent-side end. Moreover, a dust removal filter is provided at the opposite (main section-side) end to the exhaust vent, so as to cover the air duct portion. The exhaust fan rotates so as to feed air inside the cylindrical section from the main section side to the exhaust vent side. As a result, air heated by the fusing unit is collected into the main section, and passes through the cylindrical section to be ejected from the exhaust vent to the outside of the frame.
Furthermore, the fusing unit emits substances such as odorants, volatile organic compounds (referred to below as VOCs), low-molecular siloxane, and dust (e.g., toner and paper dust). Among these emissions, for example, particles of VOCs, odorants, and low-molecular siloxane are so fine that they can pass through the filter. To remove such fine particles, the image forming apparatus is provided with an ion generator that generates negative ions. Specifically, the ion generator is provided upstream of the exhaust fan in a direction in which air is fed and downstream of the filter in that air feeding direction. The ion generator generates negative ions inside the duct, so that VOCs, etc., can be neutralized by action of the negative ions, thereby reducing VOCs, etc., contained in exhaust gas.
As is apparent from the foregoing, the negative ion generator is exposed to VOC particles, etc., so that the particles adhere thereto. This results in a reduction in the amount of ion generation by the negative ion generator.